Noise source visualization data accumulation and display device, method, and acoustic camera system

ABSTRACT

A noise source visualization data accumulation and display device is provided where at two or more acoustic data are generated by beamforming acoustic signals acquired at different moments by using a plurality of microphone arrays and thereafter, one selected among two or more acoustic data or acoustic data processed therefrom is mapped to one optical image to be displayed.

BACKGROUND

The present invention relates to a noise source visualization dataaccumulation and display method and an acoustic camera system.

An acoustic camera as high tech measurement equipment visualizing soundis new technology equipment required in various fields, such as amultimedia information communication apparatus, a home appliance, anautomobile, a construction, and the like. Registration Patent No.10-1213539 (SM Instruments) possessed by an applicant of the presentinvention, which is the related art is configured by mounting aplurality of MEMS microphones on a printed circuit board and disclosesan acoustic sensing device using a MEMS microphone array, which ischaracterized in that the MEMS microphone has 2 to 10 wing parts whichextend in a radial direction.

Registration Patent No. 10-1471299 (SM Instruments) possessed by anapplicant of the present invention, which is the related art discloses amobile acoustic camera which is configured to include a front body inwhich acoustic sensing units of MEMS microphones are disposed toward thefront side; the MEMS microphones in which the acoustic sensing units areexposed to the front body while being fixed to a substrate; thesubstrate on which the MEMS microphones are mounted; an image pick-upunit in which a pick-up lens is exposed through a lens hole of the frontbody; and a rear body covering a rear side of the substrate and the rearside of the image pick-up unit while the substrate is positioned on arear surface of the front body and further include a handle unit inwhich the MEMS microphones have 2 to 30 wing parts which extend in astraight-line, curve, or spiral shape in a radial direction and 2 to 50MEMS microphones are arranged in one wing part W to be spaced apart, andwhich protrudes rearward while being fixed to a periphery of the frontbody or the rear body.

As described above, a microphone array beamformer as one of methods forinvestigating a position of a noise source is a method that measuressound waves generated from the noise source by using multiple microphonesensors and visualizes a distribution of the noise source like aphotograph through signal processing of the measured sound waves. Usedis a method that reconfigures the sound waves as a signal generated at aspecific transmitting position according to a characteristic of a signalreceived by each microphone to measure a sound pressure size of thesignal and displays a measured sound pressure level in a spatialdistribution to estimate the position of the noise source. A measurementtechnique of the acoustic camera has been developed for a researchpurpose of a special field, but is extensively applied as utilization ina research/development step of each industrial field due to an advantageof intuitively verifying the distribution of the noise source.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide an acousticcamera system that effectively discovers noise and allophone generatedat different points at different moments to display the discovered noiseand allophone so that a user easily recognize the discovered noise andallophone.

When a triggering technique using the size of simple sound pressure isused, a problem occurs, in which a noise source which becomes ameasurement analysis target is triggered when background noise byperipheral noise is turned on at the moment when noise is not generated,and as a result, a characteristic of noise to be analyzed is buried andnot displayed by undesired noise (background noise) and the presentinvention has been made in an effort to provide a noise sourcevisualization data accumulation display method and an acoustic camerasystem which solve the problem.

The present invention has been made in an effort to provide a noisesource visualization data accumulation display method and an acousticcamera system which can clearly determine positions of a plurality ofnoise sources by accumulatively displaying noise generated at differentpoints at different moments in machinery, electronic devices, vehicles,and the like on one screen and display noise levels of noise sources inorder, and exclude an influence of not a noise source region butexternal noise from a sound visualization screen by unique triggering oran effective data sorting method.

An exemplary embodiment of the present invention provides a noise sourcevisualization data accumulation display data processing device in whichat two or more acoustic data D1 and D2 are generated by beamformingacoustic signals acquired at different moments by using a plurality ofmicrophone arrays and thereafter, one selected among two or moreacoustic data or acoustic data M3 processed therefrom is mapped to oneoptical image to be displayed.

Another exemplary embodiment of the present invention provides a noisesource visualization data accumulation display data processing methodincluding: a step of providing an acoustic and image signal acquiringmeans configured to include MEMS acoustic sensors disposed to be spacedapart on a curve or a plane at a regular interval to sense an acousticsignal of a noise source, an acoustic signal acquiring unit convertingthe acoustic signal received from the MEMS acoustic sensors into adigital signal and transmitting the digital signal to a centralprocessing unit, and a pick-up lens picking up an optical image of thenoise source; an initial signal acquiring step in which the acoustic andimage signal acquiring means acquires the acoustic signal and theacoustic image of the noise source during a first time frame; an initialanalysis step in which the central processing unit calculates beam powerof each point based on the acoustic signal acquired during the firsttime frame to generate first acoustic data and generate image data basedon a signal of the pick-up lens; an initial expression step in which adisplay unit coordinates the first acoustic data and image datacalculated by the central processing unit and overlays the firstacoustic data and image data to visually express the first acoustic dataand image data; an accumulation signal acquiring step in which theacoustic signal acquiring unit acquires the acoustic signal of the noisesource during a second time frame which is temporally later than thefirst time frame; an accumulation signal analyzing step in which thecentral processing unit calculates the beam power of each point based onthe acoustic signal acquired during the second time frame to generateaccumulated acoustic data; and an accumulation expression step in whichthe display unit overlays and maps an acoustic matrix calculated byusing the second acoustic data and the initial acoustic data or thesecond acoustic data and the initial acoustic data to image data tovisually express the acoustic matrix mapped to the image data.

In the initial analysis step or the accumulation signal analyzing step,when a value calculated by using a difference value of at least two beampower values selected among beam power values of each point calculatedbased on the acoustic signal during one time frame is larger than apredetermined value, the central processing unit may treat the value asthe effective acoustic data to map the value to the image data andoverlay and display the value mapped to the image data or make the valueas a triggering signal of data storing.

In the initial analysis step or the accumulation signal analyzing step,when a difference of a maximum value P_(max) and a minimum value P_(min)among the beam power (P_(ij)) values is larger than a predeterminedreference value ΔP1 or a difference of the maximum value P_(max) and anaverage value P_(mean) is larger than a predetermined reference valueΔP2, the central processing unit may treat the value as the effectiveacoustic data to map and overlay and display the value to the image dataor make the value as the triggering signal of the data storing.

When a standard deviation value of the beam power (P_(ij)) values ofeach point calculated based on the acoustic signal acquired during onetime frame is larger than a predetermined reference, the centralprocessing unit may determine that effective noise is generated andtreats the effective noise as the effective acoustic data to map thevalue as the effective acoustic data to map the value to the image dataand overlap and display the value mapped to the image data or make thevalue as the triggering signal of the data storing.

According to the present invention, provided is an acoustic camerasystem that effectively discovers noise and allophone generated atdifferent points at different moments to display the discovered noiseand allophone so that a user easily recognize the discovered noise andallophone.

In a noise source visualization data accumulation display method and anacoustic camera system of the present invention, triggering is performedby considering whether effective noise is generated from a target noisesource due to a difference value among components of an acoustic datamatrix of one frame, which is measured in one time zone or only in thiscase, the noise is handled as effective data, and as a result, a problemis solved, in which a noise source which becomes a measurement analysistarget is triggered when background noise by peripheral noise is turnedon at the moment when noise is not generated, and as a result, acharacteristic of noise to be analyzed is buried and not displayed byundesired noise (background noise).

A noise source visualization data accumulation display method and anacoustic camera system of the present invention of the present inventioncan clearly determine positions of a plurality of noise sources byaccumulatively displaying noise generated at different points atdifferent moments in machinery, electronic devices, vehicles, and thelike on one screen and display noise levels of noise sources in order,and exclude an influence of not a noise source region but external noisefrom a sound visualization screen by unique triggering or an effectivedata sorting method.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A to 1D are explanatory diagrams of a beamforming concept.

FIGS. 2A and 2B are configuration diagrams of a source noisevisualization data accumulation display acoustic camera system.

FIG. 3 is a flowchart of a noise source visualization data accumulationdisplay method.

FIGS. 4A (overall all level: 45.1 DB) and 4B (over all level: 57.7 DB)illustrate two acoustic data (beam power levels) measured and analyzedat the same position at different time.

FIGS. 5A and 5B illustrate an acoustic data frame acquired bysubtracting an average value from a beam power level value (a matrixelement value, P_(ij)) of acoustic data displayed in matrix.

FIG. 5C illustrates an acoustic data frame in which respective matrixelement values of the acoustic data frames of FIGS. 5A and 5B areaveraged and illustrated.

FIG. 6A illustrates a method and an acoustic and image data mappingimage before noise source visualization data is accumulativelydisplayed.

FIG. 6B illustrates an acoustic and image mapping image in which noisesource visualization data is accumulatively displayed in one imageaccording to the present invention.

FIG. 7 illustrates a diagram showing values of each time frame accordingto the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1A and 1B are explanatory diagrams of a beamforming concept. Abeamforming technique may be described through an equation given below.yi(t) represents a signal measured in an i-th microphone and z(t)represents a beam output. When respective signals measured by Mmicrophone are multiplied by a weight according to a sensor by giving atime delay in a virtual sound source direction and thereafter, thesignals are added, beam power may be acquired. When directions of anactual sound source and a virtual sound source coincide with each other,the signals are amplified. By such a method, a position of a noisesource may be estimated. The beam power may be expressed by the equationgiven below.

${b(t)} = {\sum\limits_{j}\; p_{m{({t - {\Delta \; t_{j}}})}}}$

When a virtual noise source is present at a predetermined position, thesize of the noise source may be expressed by the equation given below.

${s(t)} = {\sum\limits_{j}\; {\frac{1}{r_{j}}{{ei}\left\lbrack {{kr}_{j} - {\omega \left( {t + {\Delta \; t_{j}}} \right)}} \right\rbrack}}}$

FIGS. 1A and 1B are explanatory diagrams of a beamforming concept, FIG.2 is a configuration diagram of a source noise visualization dataaccumulation display acoustic camera system,

FIG. 3 is a flowchart of a noise source visualization data accumulationdisplay method, FIGS. 4A (overall all level: 45.1 DB) and 4B (over alllevel: 57.7 DB) illustrate two acoustic data (beam power levels)measured and analyzed at the same position at different time, FIGS. 5Aand 5B illustrate an acoustic data frame acquired by subtracting anaverage value from a beam power level value (a matrix element value,P_(ij)) of acoustic data displayed in matrix, FIG. 5C illustrates anacoustic data frame in which respective matrix element values of theacoustic data frames of FIGS. 5A and 5B are averaged and illustrated,FIG. 6A illustrates a method and an acoustic and image data mappingimage before noise source visualization data is accumulativelydisplayed, and FIG. 6B illustrates an acoustic and image mapping imagein which noise source visualization data is accumulatively displayed inone image according to the present invention.

As illustrated in FIGS. 2 to 6, the noise source virtualization dataaccumulation display method of the present invention is configured toinclude a step of providing an acoustic and image signal acquiring means100 (S10), an initial signal acquiring step (S20), an initial analysisstep (S30), an initial expression step (S40), an accumulation signalacquiring step (S50), an accumulation signal analyzing step (S60), andan accumulation expression step (S70).

<Steps S10 and S20>

As illustrated in FIGS. 2A and 2B, and 3, in the step of providing theacoustic and image signal acquiring means 100 (S10), provided is anapparatus configured to include MEMS acoustic sensors 10 disposed to bespaced apart on a curve or a plane at a regular interval to sense anacoustic signal of a noise source, an acoustic signal acquiring unit 20converting the acoustic signal received from the MEMS acoustic sensors10 into a digital signal and transmitting the digital signal to acentral processing unit 40, and a pick-up lens 30 picking up an opticalimage of the noise source.

Herein, a micro electro mechanical system (MEMS) is a technology thatsimultaneously integrates a micro mechanical component having amicrometer size and an electronic circuit by applying a semiconductormanufacturing process in association with the MEMS acoustic sensors 10.A MEMS microphone measures mechanical transformation of a thin film by apressure applied to the thin film by a change in capacitance betweenelectrodes mounted in a thin-film sensor and has the same operatingprinciple as a general condenser microphone. Since the MEMS microphonedirectly measures an analog signal by digital pulse density modulation(PDM) by using an ADC, the MEMS microphone has an advantage that aseparate expensive ADC measurement device required in measurement byusing an analog sensor is not required.

In the initial signal acquiring step (S20), the acoustic and imagesignal acquiring means 100 acquires the acoustic signal and the acousticimage of the noise source during a first time frame T1. In actual, theacoustic signal acquiring unit 20 may measure the analog signal at acontinuous time interval without a pause period (only of a time sectionrecognized as effective data by analysis and determination of a centralprocessing unit is displayed and stored later).

<Steps S30 and S40>

In an exemplary embodiment (FIGS. 4A and 6A), in a first acoustic datagenerating step, the central processing unit 40 generates a beam powerlevel matrix for each point of the noise source illustrated in FIG. 4A.In the initial analysis step (S30), the central processing unit 40calculates beam power P_(ij) of each point based on the acoustic signalacquired during the first time frame T1 to generate first acoustic dataand generate image data based on a signal of the pick-up lens 30.

Herein, the acoustic data may be a beam power (P_(ij)) level of eachpoint itself or a matrix type acoustic numerical value generated basedon the beam power (P_(ij)) level of each point. Herein, the matrix typeacoustic numerical value generated based on the beam power (P_(ij))level may be, for example, a value acquired by subtracting an averagevalue from the beam power (P_(ij)) level of each point as illustrated inFIGS. 5A and 5B. Alternatively, the matrix type acoustic numerical valuemay be divided into a maximum value, the average value, an overalllevel, and the like or a normalized value by using the maximum value,the average value, the overall level, and the like.

In an exemplary embodiment (FIG. 6A-T1), in the initial expression step(S40), a first image of FIG. 6A is expressed. In the initial expressionstep (S40), a display unit 50 coordinates the first acoustic data andimage data calculated by the central processing unit 40 and overlays thefirst acoustic data and image data to visually express the firstacoustic data and image data.

<Step S50>

In an exemplary embodiment, the accumulation signal acquiring step(S50), the MEMS acoustic sensors 10 and the acoustic signal acquiringunit 20 acquire the acoustic signal of the noise source during a secondtime frame T2 which is temporally later than the first time frame T1. Inactual, the acoustic signal acquiring unit 20 will measure the analogsignal at a continuous time interval without a pause period (only of atime section recognized as effective data by analysis and determinationof a central processing unit is displayed or stored later).

<Step S60>

In an exemplary embodiment (FIGS. 4B and 6A-T2), in the accumulationsignal analyzing step(S60), the central processing unit 40 generates theacoustic matrix illustrated in FIG. 4B.

The central processing unit 40 calculates the beam power P_(ij) of eachpoint based on the acoustic signal acquired during the second time frameT2 to generate accumulated acoustic data. Herein, the acoustic data maybe a beam power (P_(ij)) level of each point itself or a matrix typeacoustic numerical value generated based on the beam power (P_(ij))level of each point. Herein, the matrix type acoustic numerical valuegenerated based on the beam power (P_(ij)) level may be, for example, avalue acquired by subtracting an average value from the beam power(P_(ij)) level of each point as illustrated in FIGS. 5A and 5B.Alternatively, the matrix type acoustic numerical value may be dividedinto a maximum value, the average value, an overall level, and the likeor a normalized value by using the maximum value, the average value, theoverall level, and the like.

<Step S70>

In an exemplary embodiment (FIGS. 5C and 6B), as illustrated in FIG. 6B,in the accumulation expression step (S70), the display unit 50 maps anddisplays second acoustic data D2 and initial acoustic data D1 or fifth,fourth, third, and second acoustic data D2, D3, D4, and D5, and theinitial acoustic data D1 in one optical image.

Herein, as illustrated in FIG. 5C, the central processing unit 40 maygenerate an acoustic matrix M3 calculated by using the second acousticdata D2 and the initial acoustic data D1 and map and display thegenerated acoustic matrix M3 in the optical image. In FIG. 5C, theacoustic matrix M calculated by using the second acoustic data D2 andthe initial acoustic data D1 represents M_(ij) acquired by averaging thedata FIGS. 5A and 5B (in this case, the calculation means an averagingoperation).

Thereafter, steps S50, S60, and S70 are repeated, for example, one timeto 10 times and in some cases, steps S50, S60, and S70 are repeated evenmore times to display noise source generation degrees at different timezones in one screen.

<Determination of Effective Data and Triggering>

In the initial analysis step (S30) or the accumulation signal analyzingstep (S60), when a value calculated by using a difference value of atleast two beam power values selected among beam power (P_(ij)) values ofeach point calculated based on the acoustic signal during one time frameis larger than a predetermined value, the central processing unit 40treats the value as the effective acoustic data to map the value to theimage data and overlay and display the value mapped to the image data ormake the value as a triggering signal of data storing.

In the initial analysis step (S30) or the accumulation signal analyzingstep (S60), when a difference of a maximum value P_(max) and a minimumvalue P_(min) among the beam power (P_(ij)) values is larger than apredetermined reference value ΔP1 or a difference of the maximum valueP_(max) and an average value P_(mean) is larger than a predeterminedreference value ΔP2, the central processing unit 40 treats the value asthe effective acoustic data to map and overlay and display the value tothe image data or make the value as the triggering signal of the datastoring. When a standard deviation value of the beam power (P_(ij))values of each point calculated based on the acoustic signal acquiredduring one time frame is larger than a predetermined reference, thecentral processing unit 40 determines that effective noise is generatedand treats the effective noise as the effective acoustic data to map thevalue as the effective acoustic data to map the value to the image dataand overlap and display the value mapped to the image data or make thevalue as the triggering signal of the data storing.

As illustrated in FIGS. 2 to 6, the noise source visualization dataaccumulation display method of the present invention is configured toinclude the MEMS acoustic sensors 10, the acoustic signal acquiring unit20, the pick-up lens 30, the central processing unit 40, and the displayunit 50. As illustrated in FIG. 2B, the MEMS acoustic sensors 10 aredisposed on a curve or a plane (not illustrated) to be spaced apart fromeach other at a regular interval to sense the acoustic signal of thenoise source. The acoustic signal acquiring unit 20 converts theacoustic signals received from the MEMS acoustic sensors 10 into digitalsignals and transmits the digital signals to the central processing unit40.

The pick-up lens 30 picks up an optical image of the noise source. Thecentral processing unit 40 calculates the beam power P_(ij) of eachpoint based on the acoustic signal acquired during a time frame togenerate acoustic data and generate image data based on a signal of thepick-up lens 30. The display unit 50 coordinates the acoustic data andthe image data calculated by the central processing unit 40 and overlaysthe first acoustic data and the image data to visually express theacoustic data and the image data.

In this case, the central processing unit 40 generates at least two ormore sound visualization images by beamforming the acoustic signalsacquired at different moments by using the MEMS acoustic sensors 10 andthe acoustic signal acquiring unit 20 and thereafter, maps the generatedsound visualization images onto one optical image acquired from thepick-up lens 30 and displays the sound visualization images mapped tothe optical image. The central processing unit 40 maps at least two ormore acoustic data by beamforming the acoustic signals acquired atdifferent moments and thereafter, normalizes the generated acoustic dataand maps the normalized acoustic data onto the optical image toaccumulate and display the acoustic data mapped onto the optical image.

The present invention has been described in association with theabove-mentioned preferred embedment, but the scope of the presentinvention is not limited to the embodiment and the scope of the presentinvention is determined by the appended claims, and thereafter, thescope of the present invention will includes various modifications andtransformations included in an equivalent range to the presentinvention.

Reference numerals disclosed in the appended claims are just used toassist appreciation of the present invention and it is revealed that thereference numerals do not influence analysis of the claims and it shouldnot be narrowly analyzed by the disclosed reference numerals.

What is claimed is:
 1. A noise source visualization data accumulationand display device, wherein two or more acoustic data (D1 and D2) aregenerated by beamforming acoustic signals acquired at different momentsby using a plurality of microphone arrays and thereafter, and whereinone selected among two or more acoustic data or acoustic data (M3)processed therefrom is mapped to one optical image to be displayed.
 2. Anoise source visualization data accumulation and display method,comprising: a step (S10) of providing an acoustic and image signalacquiring means (100) configured to include acoustic sensors (10)disposed to be spaced apart on a curve or a plane at a regular intervalto sense an acoustic signal of a noise source, an acoustic signalacquiring unit (20) converting the acoustic signal received from theacoustic sensors (10) into a digital signal and transmitting the digitalsignal to a central processing unit (40), and a pick-up lens 30 pickingup an optical image of the noise source; an initial signal acquiringstep (S20) in which the acoustic and image signal acquiring means (100)acquires the acoustic signal and the acoustic image of the noise sourceduring a first time frame (T1); an initial analysis step (S30) in whichthe central processing unit (40) calculates beam power (P_(ij)) of eachpoint based on the acoustic signal acquired during the first time frame(T1) to generate first acoustic data and generate image data based on asignal of the pick-up lens (30); an initial expression step (S40) inwhich a display unit (50) coordinates the first acoustic data and imagedata calculated by the central processing unit (40) and overlays thefirst acoustic data and image data to visually express the firstacoustic data and image data; an accumulation signal acquiring step(S50) in which the acoustic signal acquiring unit (20) acquires theacoustic signal of the noise source during a second time frame (T2)which is temporally later than the first time frame (T1); anaccumulation signal analyzing step(S60) in which the central processingunit (40) calculates the beam power (P_(ij)) of each point based on theacoustic signal acquired during the second time frame (T2) to generateaccumulated acoustic data; and an accumulation expression step (S70) inwhich the display unit (50) overlays and maps an acoustic matrix (M3)calculated by using the second acoustic data (D2) and the initialacoustic data D1 or the second acoustic data (D2) and the initialacoustic data (D1) to image data to visually express the acoustic matrix(M3) mapped to the image data.
 3. The noise source visualization dataaccumulation and display method of claim 2, wherein in the initialanalysis step (S30) or the accumulation signal analyzing step (S60),when a value calculated by using a difference value of at least two beampower values selected among beam power (P_(ij)) values of each pointcalculated based on the acoustic signal during one time frame is largerthan a predetermined value, the central processing unit (40) treats thevalue as the effective acoustic data to map the value to the image dataand overlay and display the value mapped to the image data or make thevalue as a triggering signal of data storing.
 4. The noise sourcevisualization data accumulation and display method of claim 3, whereinin the initial analysis step (S30) or the accumulation signal analyzingstep (S60), when a difference of a maximum value P_(max) and a minimumvalue (P_(min)) among the beam power (P_(ij)) values is larger than apredetermined reference value (ΔP1) or a difference of the maximum value(P_(max)) and an average value (P_(mean)) is larger than a predeterminedreference value (ΔP2), the central processing unit (40) treats the valueas the effective acoustic data to map and overlay and display the valueto the image data or make the value as the triggering signal of the datastoring.
 5. The noise source visualization data accumulation and displaymethod of claim 4, wherein when a standard deviation value of the beampower (P_(ij)) values of each point calculated based on the acousticsignal acquired during one time frame is larger than a predeterminedreference, the central processing unit (40) determines that effectivenoise is generated and treats the effective noise as the effectiveacoustic data to map the value as the effective acoustic data to map thevalue to the image data and overlap and display the value mapped to theimage data or make the value as the triggering signal of the datastoring.
 6. An acoustic camera system for a noise source visualizationdata accumulation and display, comprising: acoustic sensors (10)disposed to be spaced apart on a curve or a plane at a regular intervalto sense an acoustic signal of a noise source; an acoustic signalacquiring unit (20) converting the acoustic signal received from theacoustic sensors (10) into a digital signal and transmitting the digitalsignal to a central processing unit (40); a pick-up lens (30) picking upan optical image of the noise source; a central processing unit (40)calculating the beam power (P_(ij)) of each point based on the acousticsignal acquired during a time frame to generate acoustic data andgenerate image data based on a signal of the pick-up lens (30); and adisplay unit (50) coordinating the acoustic data and the image datacalculated by the central processing unit (40) and overlaying the firstacoustic data and the image data to visually express the acoustic dataand the image data, wherein the central processing unit (40) generatesat least two or more sound visualization images by beamforming theacoustic signals acquired at different moments by using the acousticsensors (10) and the acoustic signal acquiring unit (20) and thereafter,maps an acoustic matrix (M) calculated by using accumulated acousticdata (D2) and initial acoustic data (D1) or the accumulated acousticdata (D2) and the initial acoustic data (D1) onto one optical image anddisplays the acoustic matrix (M) mapped onto the optical image.
 7. Theacoustic camera system of claim 6, wherein the central processing unit(40) maps at least two or more acoustic data by beamforming the acousticsignals acquired at different moments and thereafter, normalizes thegenerated acoustic data and overlaps and maps the normalized acousticdata onto the optical image to display the acoustic data mapped onto theoptical image.